Livestock Genetics, International Livestock Research Institute, Addis Ababa, Ethiopia.
Department of Genetics and Animal Breeding, Faculty of Animal Production, University of Khartoum, Khartoum, Sudan.
Anim Genet. 2023 Dec;54(6):689-708. doi: 10.1111/age.13353. Epub 2023 Sep 11.
Environmental adaptation traits of indigenous African cattle are increasingly being investigated to respond to the need for sustainable livestock production in the context of unpredictable climatic changes. Several studies have highlighted genomic regions under positive selection probably associated with adaptation to environmental challenges (e.g. heat stress, trypanosomiasis, tick and tick-borne diseases). However, little attention has focused on pinpointing the candidate causative variant(s) controlling the traits. This review compiled information from 22 studies on signatures of positive selection in indigenous African cattle breeds to identify regions under positive selection. We highlight some key candidate genome regions and genes of relevance to the challenges of living in extreme environments (high temperature, high altitude, high infectious disease prevalence). They include candidate genes involved in biological pathways relating to innate and adaptive immunity (e.g. BoLAs, SPAG11, IL1RL2 and GFI1B), heat stress (e.g. HSPs, SOD1 and PRLH) and hypoxia responses (e.g. BDNF and INPP4A). Notably, the highest numbers of candidate regions are found on BTA3, BTA5 and BTA7. They overlap with genes playing roles in several biological functions and pathways. These include but are not limited to growth and feed intake, cell stability, protein stability and sweat gland development. This review may further guide targeted genome studies aiming to assess the importance of candidate causative mutations, within regulatory and protein-coding genome regions, to further understand the biological mechanisms underlying African cattle's unique adaption.
为了应对不可预测的气候变化背景下可持续畜牧业生产的需求，人们越来越多地研究非洲本土牛的环境适应特征。几项研究强调了可能与适应环境挑战（例如热应激、锥虫病、蜱和蜱传疾病）相关的受正选择作用的基因组区域。然而，很少有研究关注确定控制这些特征的候选因果变异（s）。本综述从 22 项关于非洲本土牛品种正选择特征的研究中汇总了信息，以确定受正选择作用的区域。我们强调了一些与极端环境（高温、高海拔、高传染病流行率）下生活相关的关键候选基因组区域和基因。它们包括与先天和适应性免疫相关的生物途径（例如 BoLAs、SPAG11、IL1RL2 和 GFI1B）、热应激（例如 HSPs、SOD1 和 PRLH）和缺氧反应（例如 BDNF 和 INPP4A）中涉及的候选基因。值得注意的是，在 BTA3、BTA5 和 BTA7 上发现了最多数量的候选区域。它们与在多个生物学功能和途径中发挥作用的基因重叠。这些功能和途径包括但不限于生长和饲料摄入、细胞稳定性、蛋白质稳定性和汗腺发育。本综述可能进一步指导有针对性的基因组研究，旨在评估候选因果突变在调节和蛋白质编码基因组区域中的重要性，以进一步了解非洲牛独特适应的生物学机制。
